OBJECTIVE To identify the sequence and significance of left ventricular filling abnormalities associated with progressive aging in humans. METHODS Cross-sectional study comparing three age groups. METHODS Department of Geriatrics at University of Naples. METHODS Seventy-five healthy subjects in three age groups: 25 subjects from 25 to 45 years (Group I), 25 subjects from 46 to 65 years (Group II), and 25 subjects from 66 to 85 years (Group III). METHODS None. METHODS All underwent pulsed-doppler echocardiography under color guide to measure the following parameters: peak velocity flow for early (E wave) and late (A wave) mitral flow; A/E wave ratio; deceleration time of mitral flow (MDt); isovolumic relaxation time (IRT); ratio of velocity time integrals of the A wave to the velocity time integrals of the entire mitral spectrum (VTIA/VTIM). RESULTS Peak velocity of the E wave was slightly lower in Group II and III compared to Group I; in contrast, peak velocity of the A wave was greater (P less than 0.005) in aged individuals. Also A/E wave ratio, MDt, and IRT were significantly greater with advancing age (P less than 0.01; P less than 0.05 and P less than 0.001, respectively). Finally, VTIA/VTIM tended to be greater in the oldest group, but not significantly so. CONCLUSIONS Left ventricular relaxation is progressively impaired in late middle age and old age, presumably an early marker of cardiac aging. Increased left atrial pressure is compromised only in the oldest group, presumably representing a compensation for impaired left ventricular relaxation.